Interrupts arrive to fast?

I am trying to port the driver for AHA2940 from NetBSD to VSTa.

In cam server, after receiving M_ISR, driver speciic interrupts handling
routines are called (in cam_ccb_wait()).

But when I attach the codes for AHA2940 to cam, it hangs in msg_receive.
(in cam_ccb_wait()).

I add some watch points in kernel, in order to figure out what's going on
in the dark side. It seems that interrupts arrive too fast.

The machine does not halt, the output from kernel are buffered, and being
displayed after key strikes. Times the interrupts arrive are more than
thousands, and are stored in m->arg1. (That's why I think I have no chance
to receive the message)

I don't know whether the problem is in my codes or not, if you have
experience on this before, please give me some advices on this.

// Shawn
Received on Sun Dec 10 09:44:20 1995